Typically, a personal service unit is arranged above the seating rows in passenger aircraft, in which, apart from lighting and ventilation, in particular passenger oxygen masks are also arranged, which fall downwards in order to be within the reach of the passengers in the case of a pressure drop within the cabin. For this, a compartment or container which may be closed with a flap arranged on the lower side is provided in the personal service unit, in which typically four or more passenger oxygen masks are arranged, depending on the number of seats located therebelow.
The masks always have an emergency oxygen supply flexible tube, via which they are connected to the respective stationary oxygen connection in the personal service unit. Furthermore, the masks typically yet comprise a storage bag as well as, where appropriate, an activation cord. These components are to be stored within the container in a defined arrangement, i.e. the flexible tube of each passenger oxygen mask is to be connected and rolled up in a predefined manner, and the passenger oxygen mask is then to be arranged such that it falls freely downwards on opening the flap. Thereby, the arrangement is to be effected such that the valves located in the mask are not loaded, so that they may carry out their function on later application. The ready-to-use installation of these passenger oxygen masks is therefore quite complicated in practice and in particular may not be carried out in a simple manner on account of the overhead work.
Added to this is the fact that these activities not only occur with the first installation into the aircraft, but also reoccur regularly, since the activation of the masks must be regularly checked for approval and maintenance checks.